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 (
    10076, 10945, 8864, 397, 479, 10219, 
    3317, 10188, 9848, 8880, 404, 524
  ) 
  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 0.00048

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 product_id 3 13 Using index condition; Using where

Result

product_id price
397 1446.000000
404 239.000000
479 1380.000000
524 1063.000000
3317 0.000000
8864 1391.000000
8880 1799.000000
9848 302.000000
10076 1368.000000
10188 1160.000000
10219 0.000000
10945 1016.000000