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 (
    423, 424, 455, 433, 495, 453, 468, 467, 
    420, 421, 422, 437, 494, 454, 442, 426, 
    429, 428, 438, 440, 443, 463, 460, 450, 
    446, 447, 476, 457, 482, 483, 472, 441, 
    485, 492, 479, 480, 449, 474, 473, 448, 
    493, 456, 469, 431, 466, 439, 484, 470
  ) 
  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 0.00079

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "174.46"
    },
    "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": 371,
        "rows_produced_per_join": 95,
        "filtered": "25.88",
        "cost_info": {
          "read_cost": "59.26",
          "eval_cost": "19.20",
          "prefix_cost": "78.46",
          "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 (423,424,455,433,495,453,468,467,420,421,422,437,494,454,442,426,429,428,438,440,443,463,460,450,446,447,476,457,482,483,472,441,485,492,479,480,449,474,473,448,493,456,469,431,466,439,484,470)) and (`danishecarter_latest`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}