SELECT 
  q_product_filters.filter_id, 
  q_product_features_values.variant_id 
FROM 
  q_product_features_values 
  LEFT JOIN q_products as products ON products.product_id = q_product_features_values.product_id 
  LEFT JOIN q_product_filters ON q_product_filters.feature_id = q_product_features_values.feature_id 
  LEFT JOIN q_product_features ON q_product_features.feature_id = q_product_features_values.feature_id 
  LEFT JOIN q_product_options_inventory as inventory ON inventory.product_id = products.product_id 
  LEFT JOIN q_companies AS companies ON companies.company_id = products.company_id 
  INNER JOIN q_products_categories as products_categories ON products_categories.product_id = products.product_id 
  INNER JOIN q_categories ON q_categories.category_id = products_categories.category_id 
  AND (
    q_categories.usergroup_ids = '' 
    OR FIND_IN_SET(0, q_categories.usergroup_ids) 
    OR FIND_IN_SET(1, q_categories.usergroup_ids)
  ) 
  AND q_categories.status IN ('A', 'H') 
WHERE 
  q_product_filters.filter_id IN (1, 3, 11) 
  AND q_product_features_values.feature_id IN (2, 7) 
  AND q_product_features_values.lang_code = 'en' 
  AND q_categories.category_id IN (39) 
  AND companies.status = 'A' 
  AND (
    CASE products.tracking WHEN 'O' THEN inventory.amount > 0 WHEN 'B' THEN products.amount > 0 ELSE 1 END
  ) 
  AND (
    products.usergroup_ids = '' 
    OR FIND_IN_SET(0, products.usergroup_ids) 
    OR FIND_IN_SET(1, products.usergroup_ids)
  ) 
  AND products.status IN ('A') 
  AND q_product_features.feature_type IN ('S', 'M', 'E') 
GROUP BY 
  q_product_features_values.variant_id

Query time 0.00759

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "253.43"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "28.28"
      },
      "nested_loop": [
        {
          "table": {
            "table_name": "inventory",
            "access_type": "system",
            "possible_keys": [
              "pc"
            ],
            "rows_examined_per_scan": 0,
            "rows_produced_per_join": 1,
            "filtered": "0.00",
            "const_row_not_found": true,
            "cost_info": {
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              "prefix_cost": "0.00",
              "data_read_per_join": "976"
            },
            "used_columns": [
              "product_id",
              "amount"
            ]
          }
        },
        {
          "table": {
            "table_name": "q_categories",
            "access_type": "const",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
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            "ref": [
              "const"
            ],
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            "cost_info": {
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            "used_columns": [
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            ]
          }
        },
        {
          "table": {
            "table_name": "q_product_filters",
            "access_type": "range",
            "possible_keys": [
              "PRIMARY",
              "feature_id"
            ],
            "key": "feature_id",
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            ],
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            "index_condition": "((`portal`.`q_product_filters`.`feature_id` in (2,7)) and (`portal`.`q_product_filters`.`feature_id` is not null))",
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            },
            "used_columns": [
              "filter_id",
              "feature_id"
            ],
            "attached_condition": "(`portal`.`q_product_filters`.`filter_id` in (1,3,11))"
          }
        },
        {
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            "table_name": "q_product_features",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "feature_id"
            ],
            "key_length": "3",
            "ref": [
              "portal.q_product_filters.feature_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 0,
            "filtered": "30.00",
            "cost_info": {
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            },
            "used_columns": [
              "feature_id",
              "feature_type"
            ],
            "attached_condition": "(`portal`.`q_product_features`.`feature_type` in ('S','M','E'))"
          }
        },
        {
          "table": {
            "table_name": "products_categories",
            "access_type": "ref",
            "possible_keys": [
              "PRIMARY",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "const"
            ],
            "rows_examined_per_scan": 675,
            "rows_produced_per_join": 303,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "8.03",
              "eval_cost": "60.75",
              "prefix_cost": "73.89",
              "data_read_per_join": "4K"
            },
            "used_columns": [
              "product_id",
              "category_id"
            ],
            "attached_condition": "(`portal`.`products_categories`.`product_id` is not null)"
          }
        },
        {
          "table": {
            "table_name": "products",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY",
              "status"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "product_id"
            ],
            "key_length": "3",
            "ref": [
              "portal.products_categories.product_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 282,
            "filtered": "93.11",
            "cost_info": {
              "read_cost": "0.00",
              "eval_cost": "56.56",
              "prefix_cost": "134.64",
              "data_read_per_join": "1M"
            },
            "used_columns": [
              "product_id",
              "status",
              "company_id",
              "amount",
              "usergroup_ids",
              "tracking"
            ],
            "attached_condition": "((case `portal`.`products`.`tracking` when 'O' then <cache>((NULL > 0)) when 'B' then (`portal`.`products`.`amount` > 0) else 1 end) and ((`portal`.`products`.`usergroup_ids` = '') or find_in_set(0,`portal`.`products`.`usergroup_ids`) or find_in_set(1,`portal`.`products`.`usergroup_ids`)) and (`portal`.`products`.`status` = 'A'))"
          }
        },
        {
          "table": {
            "table_name": "companies",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "company_id"
            ],
            "key_length": "4",
            "ref": [
              "portal.products.company_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 28,
            "filtered": "10.00",
            "cost_info": {
              "read_cost": "0.00",
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              "prefix_cost": "191.21",
              "data_read_per_join": "156K"
            },
            "used_columns": [
              "company_id",
              "status"
            ],
            "attached_condition": "(`portal`.`companies`.`status` = 'A')"
          }
        },
        {
          "table": {
            "table_name": "q_product_features_values",
            "access_type": "ref",
            "possible_keys": [
              "PRIMARY",
              "fl",
              "variant_id",
              "lang_code",
              "product_id",
              "fpl"
            ],
            "key": "fpl",
            "used_key_parts": [
              "feature_id",
              "product_id",
              "lang_code"
            ],
            "key_length": "12",
            "ref": [
              "portal.q_product_filters.feature_id",
              "portal.products_categories.product_id",
              "const"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 28,
            "filtered": "100.00",
            "cost_info": {
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              "prefix_cost": "225.14",
              "data_read_per_join": "21K"
            },
            "used_columns": [
              "feature_id",
              "product_id",
              "variant_id",
              "lang_code"
            ]
          }
        }
      ]
    }
  }
}