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 (
    10800, 10799, 10798, 10797, 10796, 10795, 
    10794, 10793, 10792, 10791, 10790, 
    10789, 10788, 10787, 10786, 10785, 
    10784, 10783, 10782, 10781, 10780, 
    10779, 10778, 10777, 10776, 10775, 
    10774, 10773, 10772, 10771, 10770, 
    10769
  ) 
  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 0.00052

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": 32,
      "filtered": 99.23484039,
      "index_condition": "cscart_product_prices.product_id in (10800,10799,10798,10797,10796,10795,10794,10793,10792,10791,10790,10789,10788,10787,10786,10785,10784,10783,10782,10781,10780,10779,10778,10777,10776,10775,10774,10773,10772,10771,10770,10769)",
      "attached_condition": "cscart_product_prices.lower_limit = 1 and cscart_product_prices.usergroup_id in (0,1)"
    }
  }
}

Result

product_id price
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
10778 2106.01000000
10779 2106.01000000
10780 2106.01000000
10781 2106.01000000
10782 2106.01000000
10783 2106.01000000
10784 2106.01000000
10785 2106.01000000
10786 2106.01000000
10787 2106.01000000
10788 2106.01000000
10789 2106.01000000
10790 2106.01000000
10791 2106.01000000
10792 1582.30000000
10793 1582.30000000
10794 1582.30000000
10795 1582.30000000
10796 1582.30000000
10797 1582.30000000
10798 1582.30000000
10799 1582.30000000
10800 1582.30000000