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 (
    94262, 93316, 95080, 94904, 94798, 94060, 
    92913, 94880, 94870, 94869, 94867, 
    94821, 94759, 94686, 94017, 94016, 
    94015, 94014, 94013, 94012
  ) 
  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 0.00070

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 40 Using where

Result

product_id price
92913 1.69000000
93316 1.69000000
94012 1.69000000
94013 1.69000000
94014 1.69000000
94015 1.69000000
94016 1.69000000
94017 8.99000000
94060 1.69000000
94262 1.69000000
94686 1.69000000
94759 1.69000000
94798 1.69000000
94821 1.69000000
94867 1.69000000
94869 1.69000000
94870 1.69000000
94880 1.69000000
94904 1.69000000
95080 1.69000000