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 (
    1124294, 1660912, 1661197, 1658864, 
    1657833, 1660621, 1658593, 1658265, 
    1658811, 1664157, 1660401, 1660547, 
    1662451, 1658506, 1657840, 1658270, 
    1660154, 1663612, 1659246, 1658504, 
    1658427, 1663182, 1659564, 1661697, 
    1658557, 1659832, 1663613, 1659562, 
    1659920, 1657700, 1659922, 1661022
  ) 
  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 0.00289

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "72.63"
    },
    "grouping_operation": {
      "using_filesort": false,
      "table": {
        "table_name": "cscart_product_prices",
        "access_type": "range",
        "possible_keys": [
          "usergroup",
          "product_id",
          "lower_limit",
          "usergroup_id"
        ],
        "key": "usergroup",
        "used_key_parts": [
          "product_id",
          "usergroup_id",
          "lower_limit"
        ],
        "key_length": "9",
        "rows_examined_per_scan": 64,
        "rows_produced_per_join": 64,
        "filtered": "100.00",
        "cost_info": {
          "read_cost": "66.23",
          "eval_cost": "6.40",
          "prefix_cost": "72.63",
          "data_read_per_join": "1K"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`maniamall_cscart`.`cscart_product_prices`.`lower_limit` = 1) and (`maniamall_cscart`.`cscart_product_prices`.`product_id` in (1124294,1660912,1661197,1658864,1657833,1660621,1658593,1658265,1658811,1664157,1660401,1660547,1662451,1658506,1657840,1658270,1660154,1663612,1659246,1658504,1658427,1663182,1659564,1661697,1658557,1659832,1663613,1659562,1659920,1657700,1659922,1661022)) and (`maniamall_cscart`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}

Result