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 (
    5939, 6012, 6013, 6014, 6015, 6016, 6017, 
    6018, 6019, 6020, 6196, 6197, 6198, 
    6199, 6200, 6732, 2836, 2837, 2838, 
    2839, 2840, 6422, 6423, 6424, 6425, 
    2937, 2938, 2939, 2940, 2941, 6522, 
    6523, 6524, 6525, 2189, 2190, 2191, 
    2192, 2193, 2194, 2195, 2196, 2197, 
    2720, 2721, 2722, 2723, 2769
  ) 
  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 0.00034

JSON explain

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