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 (
    10785, 10786, 10787, 10788, 10789, 10790, 
    10791, 10767, 10768, 10769, 10770, 
    10771, 10772, 10773, 10774, 10775, 
    10776, 10777, 12944, 12985, 12986, 
    12987, 12988, 12989, 12990, 12991, 
    12992, 12993, 12994, 10063, 10052, 
    10072, 10046, 10059, 10064, 10057, 
    10048, 10062, 10070, 10058, 10045, 
    10054, 10047, 10071, 10067, 10051, 
    10060, 10055, 10043, 10068, 10065, 
    10061, 10050, 10056, 10044, 10069, 
    10066, 10024, 10025, 10026, 10027, 
    10028, 10029, 10030
  ) 
  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 0.00098

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": 64,
      "filtered": 99.23484039,
      "index_condition": "cscart_product_prices.product_id in (10785,10786,10787,10788,10789,10790,10791,10767,10768,10769,10770,10771,10772,10773,10774,10775,10776,10777,12944,12985,12986,12987,12988,12989,12990,12991,12992,12993,12994,10063,10052,10072,10046,10059,10064,10057,10048,10062,10070,10058,10045,10054,10047,10071,10067,10051,10060,10055,10043,10068,10065,10061,10050,10056,10044,10069,10066,10024,10025,10026,10027,10028,10029,10030)",
      "attached_condition": "cscart_product_prices.lower_limit = 1 and cscart_product_prices.usergroup_id in (0,1)"
    }
  }
}

Result

product_id price
10024 1716.01000000
10025 1716.01000000
10026 1716.01000000
10027 1716.01000000
10028 1716.01000000
10029 1716.01000000
10030 1716.01000000
10043 1929.60000000
10044 1929.60000000
10045 1672.00000000
10046 1929.60000000
10047 1929.60000000
10048 1929.60000000
10050 1929.60000000
10051 1929.60000000
10052 1929.60000000
10054 1929.60000000
10055 1929.60000000
10056 1929.60000000
10057 1929.60000000
10058 1929.60000000
10059 1929.60000000
10060 1929.60000000
10061 1929.60000000
10062 1929.60000000
10063 1929.60000000
10064 1929.60000000
10065 1929.60000000
10066 1929.60000000
10067 1929.60000000
10068 1929.60000000
10069 1929.60000000
10070 1929.60000000
10071 1929.60000000
10072 1929.60000000
10767 5972.60000000
10768 5972.60000000
10769 5972.60000000
10770 5972.60000000
10771 5972.60000000
10772 5972.60000000
10773 5972.60000000
10774 5972.60000000
10775 5972.60000000
10776 5972.60000000
10777 5972.60000000
10785 2106.01000000
10786 2106.01000000
10787 2106.01000000
10788 2106.01000000
10789 2106.01000000
10790 2106.01000000
10791 2106.01000000
12944 1560.00000000
12985 921.36000000
12986 921.36000000
12987 921.36000000
12988 921.36000000
12989 921.36000000
12990 921.36000000
12991 921.36000000
12992 921.36000000
12993 921.36000000
12994 921.36000000