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 (
    62636, 62635, 62634, 62633, 62632, 62631, 
    62630, 62629, 62628, 62627, 62626, 
    62625, 62611, 62609, 62607, 62569, 
    62456, 61887, 60269, 62370, 62342, 
    62098, 62097, 61770, 61769, 61704, 
    60784, 60268, 62217, 61403, 61442, 
    62055, 61886, 61768, 60787, 60267, 
    62105, 61512, 62019, 61960
  ) 
  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 0.00146

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 80 Using where

Result

product_id price
60267 1.69000000
60268 1.69000000
60269 1.69000000
60784 1.69000000
60787 1.69000000
61403 1.69000000
61442 1.69000000
61512 1.69000000
61704 1.69000000
61768 1.69000000
61769 1.69000000
61770 1.69000000
61886 1.69000000
61887 1.69000000
61960 1.69000000
62019 1.69000000
62055 1.69000000
62097 1.69000000
62098 1.69000000
62105 1.69000000
62217 1.69000000
62342 1.69000000
62370 1.69000000
62456 1.69000000
62569 1.69000000
62607 1.69000000
62609 1.69000000
62611 1.69000000
62625 1.69000000
62626 1.69000000
62627 1.69000000
62628 1.69000000
62629 1.69000000
62630 1.69000000
62631 1.69000000
62632 1.69000000
62633 1.69000000
62634 1.69000000
62635 1.69000000
62636 1.69000000