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 (
    105249, 105248, 105247, 105246, 105245, 
    105244, 105243, 105242, 105241, 105240
  ) 
  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 0.00047

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 20 Using where

Result

product_id price
105240 1.69000000
105241 1.69000000
105242 1.69000000
105243 1.69000000
105244 1.69000000
105245 1.69000000
105246 1.69000000
105247 1.69000000
105248 1.69000000
105249 1.69000000