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 (
    74405, 74404, 74403, 74402, 74401, 74400, 
    74399, 74398, 74397, 74396, 74395, 
    74394, 73974, 74268, 74180, 74091, 
    73995, 73744, 74267, 73822, 73690, 
    73601, 74090, 74089, 74088, 74087, 
    74086, 74085, 74084, 74083, 74082, 
    74081, 74080, 74079, 74078, 74077, 
    74076, 74075, 74074, 74073
  ) 
  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 0.00060

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE cscart_ult_product_prices range usergroup,product_id,company_id,lower_limit,usergroup_id usergroup 13 1 Using where