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 (
    367, 368, 369, 370, 355, 356, 357, 358, 
    359, 360, 361, 362, 352, 353, 354, 350, 
    349, 346, 345, 331, 335, 339, 341, 315, 
    289, 287, 286, 278, 280, 282, 247, 248
  ) 
  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 0.00085

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 (367,368,369,370,355,356,357,358,359,360,361,362,352,353,354,350,349,346,345,331,335,339,341,315,289,287,286,278,280,282,247,248)) and (`pankajecarter_systemfour`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}