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 (
    419, 418, 417, 416, 415, 414, 413, 412, 
    411, 410, 409, 407, 406, 405, 403, 404, 
    402, 401, 278, 280, 282, 247, 248, 241, 
    244, 245, 246, 240, 6, 66, 166, 214, 219, 
    221, 223, 192, 194, 195, 196, 197, 198, 
    199, 200, 201, 202, 203, 204, 205
  ) 
  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 0.00064

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "173.31"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "96.00"
      },
      "table": {
        "table_name": "cscart_product_prices",
        "access_type": "ALL",
        "possible_keys": [
          "usergroup",
          "product_id",
          "lower_limit",
          "usergroup_id"
        ],
        "rows_examined_per_scan": 368,
        "rows_produced_per_join": 95,
        "filtered": "26.09",
        "cost_info": {
          "read_cost": "58.11",
          "eval_cost": "19.20",
          "prefix_cost": "77.31",
          "data_read_per_join": "2K"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`danishecarter_latest`.`cscart_product_prices`.`lower_limit` = 1) and (`danishecarter_latest`.`cscart_product_prices`.`product_id` in (419,418,417,416,415,414,413,412,411,410,409,407,406,405,403,404,402,401,278,280,282,247,248,241,244,245,246,240,6,66,166,214,219,221,223,192,194,195,196,197,198,199,200,201,202,203,204,205)) and (`danishecarter_latest`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}