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 (
    37553, 37554, 37555, 37557, 37558, 37559, 
    37560, 37561, 37562, 37563, 37820, 
    37821, 37822, 37823, 37824, 37825, 
    37826, 37827, 37832, 37833, 37850, 
    37858, 37862, 37864, 37867, 37868, 
    37869, 37872, 37873, 37874
  ) 
  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 0.00095

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "104.21"
    },
    "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": 53,
        "rows_produced_per_join": 10,
        "filtered": "19.99",
        "index_condition": "(`portal`.`q_product_prices`.`product_id` in (37553,37554,37555,37557,37558,37559,37560,37561,37562,37563,37820,37821,37822,37823,37824,37825,37826,37827,37832,37833,37850,37858,37862,37864,37867,37868,37869,37872,37873,37874))",
        "cost_info": {
          "read_cost": "102.09",
          "eval_cost": "2.12",
          "prefix_cost": "104.21",
          "data_read_per_join": "254"
        },
        "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)))"
      }
    }
  }
}