SELECT 
  q_product_prices.product_id, 
  MIN(
    IF(
      q_product_prices.percentage_discount = 0, 
      q_product_prices.price, 
      q_product_prices.price - (
        q_product_prices.price * q_product_prices.percentage_discount
      )/ 100
    )
  ) AS price 
FROM 
  q_product_prices 
WHERE 
  q_product_prices.product_id IN (
    9170, 9171, 9172, 9173, 9174, 9175, 9176, 
    9177, 9178, 9179, 9180, 9181, 9182, 
    9183, 9185, 9186, 9187, 9188, 9189, 
    9190, 9191, 9192, 9193, 9194, 9195, 
    9196, 9197, 9198, 9199, 9200, 9201, 
    9202
  ) 
  AND q_product_prices.lower_limit = 1 
  AND q_product_prices.usergroup_id IN (0, 1) 
GROUP BY 
  q_product_prices.product_id

Query time 0.00099

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "96.41"
    },
    "grouping_operation": {
      "using_filesort": false,
      "table": {
        "table_name": "q_product_prices",
        "access_type": "range",
        "possible_keys": [
          "usergroup",
          "product_id",
          "lower_limit",
          "usergroup_id"
        ],
        "key": "product_id",
        "used_key_parts": [
          "product_id"
        ],
        "key_length": "3",
        "rows_examined_per_scan": 46,
        "rows_produced_per_join": 9,
        "filtered": "19.99",
        "index_condition": "(`portal`.`q_product_prices`.`product_id` in (9170,9171,9172,9173,9174,9175,9176,9177,9178,9179,9180,9181,9182,9183,9185,9186,9187,9188,9189,9190,9191,9192,9193,9194,9195,9196,9197,9198,9199,9200,9201,9202))",
        "cost_info": {
          "read_cost": "94.57",
          "eval_cost": "1.84",
          "prefix_cost": "96.41",
          "data_read_per_join": "220"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`portal`.`q_product_prices`.`lower_limit` = 1) and (`portal`.`q_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}