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 (
    120, 223, 225, 224, 146, 147, 93, 117, 
    219, 222, 220, 221, 87, 113, 139, 118, 
    83, 157, 286, 123, 174, 171, 280, 282, 
    278, 331, 335, 339, 341, 355, 356, 357
  ) 
  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 0.00082

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "144.45"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "64.00"
      },
      "table": {
        "table_name": "cscart_product_prices",
        "access_type": "ALL",
        "possible_keys": [
          "usergroup",
          "product_id",
          "lower_limit",
          "usergroup_id"
        ],
        "rows_examined_per_scan": 383,
        "rows_produced_per_join": 64,
        "filtered": "16.71",
        "cost_info": {
          "read_cost": "67.66",
          "eval_cost": "12.80",
          "prefix_cost": "80.46",
          "data_read_per_join": "1K"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`pankajecarter_systemfour`.`cscart_product_prices`.`lower_limit` = 1) and (`pankajecarter_systemfour`.`cscart_product_prices`.`product_id` in (120,223,225,224,146,147,93,117,219,222,220,221,87,113,139,118,83,157,286,123,174,171,280,282,278,331,335,339,341,355,356,357)) and (`pankajecarter_systemfour`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}