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 (
    1233005, 1233008, 1233011, 1233012, 
    1233004, 1233001, 1232994, 1232998, 
    1232999, 1233020, 1233022, 1238147, 
    1238155, 1238164, 1238132, 1238131, 
    1233023, 1238120, 1238126, 1232993, 
    1232979, 1232940, 1232935, 1232906, 
    1232897, 1232946, 1232908, 1232977, 
    1232975, 1232947, 1232971, 1232966, 
    1232953, 1232965, 1232973
  ) 
  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 0.00382

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "83.52"
    },
    "grouping_operation": {
      "using_filesort": false,
      "table": {
        "table_name": "cscart_product_prices",
        "access_type": "range",
        "possible_keys": [
          "usergroup",
          "product_id",
          "lower_limit",
          "usergroup_id"
        ],
        "key": "usergroup",
        "used_key_parts": [
          "product_id",
          "usergroup_id",
          "lower_limit"
        ],
        "key_length": "9",
        "rows_examined_per_scan": 70,
        "rows_produced_per_join": 70,
        "filtered": "100.00",
        "cost_info": {
          "read_cost": "76.52",
          "eval_cost": "7.00",
          "prefix_cost": "83.52",
          "data_read_per_join": "1K"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`maniamall_cscart`.`cscart_product_prices`.`lower_limit` = 1) and (`maniamall_cscart`.`cscart_product_prices`.`product_id` in (1233005,1233008,1233011,1233012,1233004,1233001,1232994,1232998,1232999,1233020,1233022,1238147,1238155,1238164,1238132,1238131,1233023,1238120,1238126,1232993,1232979,1232940,1232935,1232906,1232897,1232946,1232908,1232977,1232975,1232947,1232971,1232966,1232953,1232965,1232973)) and (`maniamall_cscart`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}

Result