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 (
    3113, 6687, 6699, 36, 37, 38, 39, 40, 41, 
    42, 83, 84, 85, 86, 87, 88, 89, 147, 148, 
    149, 150, 151, 152, 153, 168, 169, 170, 
    171, 172, 173, 174, 250, 251, 252, 253, 
    254, 255, 256, 304, 305, 306, 307, 308, 
    309, 3532, 3533, 3534, 3535, 3536, 3537, 
    3538, 3947, 3948, 3949, 3950, 3951, 
    3952, 3953, 3992, 3993, 3994, 3995, 
    3996, 3997, 3998, 4052, 4053, 4054, 
    4055, 4056, 4057, 4058, 4135, 4136, 
    4137, 4138, 4139, 4140, 4141, 4188, 
    4189, 4190, 4191, 4192, 4193, 4194, 
    29, 30, 31, 32, 33, 34, 35, 76, 77, 78
  ) 
  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 0.00158

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 (3113,6687,6699,36,37,38,39,40,41,42,83,84,85,86,87,88,89,147,148,149,150,151,152,153,168,169,170,171,172,173,174,250,251,252,253,254,255,256,304,305,306,307,308,309,3532,3533,3534,3535,3536,3537,3538,3947,3948,3949,3950,3951,3952,3953,3992,3993,3994,3995,3996,3997,3998,4052,4053,4054,4055,4056,4057,4058,4135,4136,4137,4138,4139,4140,4141,4188,4189,4190,4191,4192,4193,4194,29,30,31,32,33,34,35,76,77,78))",
        "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)))"
      }
    }
  }
}