SELECT 
  cscart_ult_product_prices.product_id, 
  MIN(
    IF(
      cscart_ult_product_prices.percentage_discount = 0, 
      cscart_ult_product_prices.price, 
      cscart_ult_product_prices.price - (
        cscart_ult_product_prices.price * cscart_ult_product_prices.percentage_discount
      )/ 100
    )
  ) AS price 
FROM 
  cscart_ult_product_prices 
WHERE 
  cscart_ult_product_prices.product_id IN (
    255961, 255970, 260992, 261904, 285179, 
    285196, 295915, 315813, 141322, 163581, 
    183619, 210845, 223011, 225199, 236271, 
    238472, 253367, 285186, 285188, 295887, 
    308293, 308343, 308345, 317513
  ) 
  AND cscart_ult_product_prices.lower_limit = 1 
  AND cscart_ult_product_prices.company_id = 1 
  AND cscart_ult_product_prices.usergroup_id IN (0, 0, 1) 
GROUP BY 
  cscart_ult_product_prices.product_id

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}