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 (
    94016, 94015, 94014, 94013, 94012, 94011, 
    94010, 94009, 94008, 94007, 94006
  ) 
  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 0.00038

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE cscart_product_prices range usergroup,product_id,lower_limit,usergroup_id usergroup 9 22 Using where

Result

product_id price
94006 1.69000000
94007 1.69000000
94008 1.69000000
94009 1.69000000
94010 1.69000000
94011 1.69000000
94012 1.69000000
94013 1.69000000
94014 1.69000000
94015 1.69000000
94016 1.69000000