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 (
    85626, 85625, 85184, 85181, 85180, 85178, 
    85177, 85176, 85175, 85174, 85172, 
    85170, 85168, 85167, 85165, 85164, 
    34046, 34045, 34044, 85509, 85216, 
    85215, 85214, 85213, 85212, 85211, 
    85210, 85209, 85208, 85432, 85431, 
    85430, 85429, 85428, 85427, 85426, 
    85425, 85424, 85423, 85422
  ) 
  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 0.00066

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