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 (
    10926, 10620, 10920, 10719, 10746, 10717, 
    10862, 10679, 10891, 10693, 10590, 
    10727, 10705, 10629, 10898, 10610, 
    10592, 10749, 10668, 10722, 10856, 
    10886, 10922, 10601, 10897, 10588, 
    10675, 10785, 10779, 10624, 10754, 
    10880, 10740, 10729, 10787, 10628, 
    10713, 10627, 10691, 10769, 10598, 
    10690, 10887, 10747, 10832, 10901, 
    10908, 10833, 10730, 10805
  ) 
  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 0.00157

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "35.01"
    },
    "grouping_operation": {
      "using_filesort": false,
      "table": {
        "table_name": "cscart_product_prices",
        "access_type": "range",
        "possible_keys": [
          "usergroup",
          "product_id",
          "lower_limit",
          "usergroup_id"
        ],
        "key": "product_id",
        "used_key_parts": [
          "product_id"
        ],
        "key_length": "3",
        "rows_examined_per_scan": 50,
        "rows_produced_per_join": 9,
        "filtered": "20.00",
        "index_condition": "(`cscartdb`.`cscart_product_prices`.`product_id` in (10926,10620,10920,10719,10746,10717,10862,10679,10891,10693,10590,10727,10705,10629,10898,10610,10592,10749,10668,10722,10856,10886,10922,10601,10897,10588,10675,10785,10779,10624,10754,10880,10740,10729,10787,10628,10713,10627,10691,10769,10598,10690,10887,10747,10832,10901,10908,10833,10730,10805))",
        "cost_info": {
          "read_cost": "34.01",
          "eval_cost": "1.00",
          "prefix_cost": "35.01",
          "data_read_per_join": "239"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`cscartdb`.`cscart_product_prices`.`lower_limit` = 1) and (`cscartdb`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}