SELECT 
  cscart_product_prices.product_id, 
  MIN(
    IF(
      cscart_product_prices.percentage_discount = 0, 
      cscart_product_prices.price, 
      cscart_product_prices.price - (
        cscart_product_prices.price * cscart_product_prices.percentage_discount
      )/ 100
    )
  ) AS price 
FROM 
  cscart_product_prices 
WHERE 
  cscart_product_prices.product_id IN (
    231, 232, 264, 265, 266, 267, 268, 269, 
    270, 318, 319, 320, 321, 322, 323, 3961, 
    3962, 3963, 3964, 3965, 3966, 3967, 
    4006, 4007, 4008, 4009, 4010, 4011, 
    4012, 4066, 4067, 4068, 4069, 4070, 
    4071, 4072, 4073, 4074, 4075, 4076, 
    4077, 4078, 4079, 4110, 4111, 4112, 
    4113, 4114, 4115, 4116, 4149, 4150, 
    4151, 4152, 4153, 4154, 4155, 4202, 
    4203, 4204, 4205, 4206, 4207, 4208, 
    3109, 3123, 6671, 6676, 6684, 5, 6, 7, 
    8, 9, 10, 11, 57, 58, 59, 60, 61, 62, 63, 
    111, 112, 113, 114, 115, 116, 117, 210, 
    211, 212, 213, 214, 215
  ) 
  AND cscart_product_prices.lower_limit = 1 
  AND cscart_product_prices.usergroup_id IN (0, 1) 
GROUP BY 
  cscart_product_prices.product_id

Query time 0.00131

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "67.66"
    },
    "grouping_operation": {
      "using_filesort": false,
      "table": {
        "table_name": "cscart_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": 97,
        "rows_produced_per_join": 19,
        "filtered": "20.00",
        "index_condition": "(`gaseus`.`cscart_product_prices`.`product_id` in (231,232,264,265,266,267,268,269,270,318,319,320,321,322,323,3961,3962,3963,3964,3965,3966,3967,4006,4007,4008,4009,4010,4011,4012,4066,4067,4068,4069,4070,4071,4072,4073,4074,4075,4076,4077,4078,4079,4110,4111,4112,4113,4114,4115,4116,4149,4150,4151,4152,4153,4154,4155,4202,4203,4204,4205,4206,4207,4208,3109,3123,6671,6676,6684,5,6,7,8,9,10,11,57,58,59,60,61,62,63,111,112,113,114,115,116,117,210,211,212,213,214,215))",
        "cost_info": {
          "read_cost": "65.72",
          "eval_cost": "1.94",
          "prefix_cost": "67.66",
          "data_read_per_join": "465"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`gaseus`.`cscart_product_prices`.`lower_limit` = 1) and (`gaseus`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}