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 (
    10768, 10767, 10766, 10765, 10764, 10763, 
    10762, 10761, 10760, 10759, 10758, 
    10757, 10756, 10755, 10754, 10753, 
    10752, 10751, 10750, 10749, 10748, 
    10747, 15736, 15737, 15738, 15739, 
    15740, 15741, 15742, 15743, 15745, 
    15746, 15744, 12632, 12633, 10179, 
    10180, 10523, 10073, 10077, 10076, 
    10086, 10085, 10084, 10083, 10082, 
    10081, 10080, 10079, 10584, 10594, 
    12574, 10168, 10167, 12703, 15968, 
    15938, 10053, 10041, 9904, 9905, 15966, 
    15965, 9940
  ) 
  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 0.00102

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_prices",
      "access_type": "range",
      "possible_keys": ["usergroup", "product_id", "lower_limit", "usergroup_id"],
      "key": "product_id",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 128,
      "filtered": 100,
      "index_condition": "cscart_product_prices.product_id in (10768,10767,10766,10765,10764,10763,10762,10761,10760,10759,10758,10757,10756,10755,10754,10753,10752,10751,10750,10749,10748,10747,15736,15737,15738,15739,15740,15741,15742,15743,15745,15746,15744,12632,12633,10179,10180,10523,10073,10077,10076,10086,10085,10084,10083,10082,10081,10080,10079,10584,10594,12574,10168,10167,12703,15968,15938,10053,10041,9904,9905,15966,15965,9940)",
      "attached_condition": "cscart_product_prices.lower_limit = 1 and cscart_product_prices.usergroup_id in (0,1)"
    }
  }
}

Result

product_id price
9904 1849.73000000
9905 1849.73000000
9940 2142.00000000
10041 1849.73000000
10053 1955.00000000
10073 1660.30000000
10076 1660.30000000
10077 1660.30000000
10079 1660.30000000
10080 1660.30000000
10081 1660.30000000
10082 1660.30000000
10083 1660.30000000
10084 1660.30000000
10085 1660.30000000
10086 1660.30000000
10167 1849.73000000
10168 1849.73000000
10179 1660.30000000
10180 1660.30000000
10523 1660.30000000
10584 1660.30000000
10594 1660.30000000
10747 6184.31000000
10748 6184.31000000
10749 6184.31000000
10750 6184.31000000
10751 6184.31000000
10752 6184.31000000
10753 7644.03000000
10754 7644.03000000
10755 7644.03000000
10756 7644.03000000
10757 7644.03000000
10758 7644.03000000
10759 3264.87000000
10760 3264.87000000
10761 3264.87000000
10762 3264.87000000
10763 3264.87000000
10764 3264.87000000
10765 3264.87000000
10766 3264.87000000
10767 5972.60000000
10768 5972.60000000
12574 78181.27000000
12632 67629.15000000
12633 67629.15000000
12703 1849.73000000
15736 3955.73000000
15737 3955.73000000
15738 3955.73000000
15739 3955.73000000
15740 3955.73000000
15741 3955.73000000
15742 3955.73000000
15743 3955.73000000
15744 3000.00000000
15745 3955.73000000
15746 3955.73000000
15938 4889.00000000
15965 6424.00000000
15966 5975.00000000
15968 4889.00000000