SELECT 
  cscart_ult_product_prices.product_id, 
  MIN(
    IF(
      cscart_ult_product_prices.percentage_discount = 0, 
      cscart_ult_product_prices.price, 
      cscart_ult_product_prices.price - (
        cscart_ult_product_prices.price * cscart_ult_product_prices.percentage_discount
      )/ 100
    )
  ) AS price 
FROM 
  cscart_ult_product_prices 
WHERE 
  cscart_ult_product_prices.product_id IN (
    11315, 11308, 10945, 10936, 10935, 10934, 
    10933, 10900, 10899, 10568, 10572, 
    10570, 10567, 10574, 10511, 9952, 9878, 
    9422, 9242, 9240, 9252, 9253, 9254, 
    9255, 9256, 8666, 9453, 8580, 8568, 
    8579
  ) 
  AND cscart_ult_product_prices.lower_limit = 1 
  AND cscart_ult_product_prices.company_id = 1 
  AND cscart_ult_product_prices.usergroup_id IN (0, 0, 1) 
GROUP BY 
  cscart_ult_product_prices.product_id

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "3.40"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "table": {
        "table_name": "cscart_ult_product_prices",
        "access_type": "ref",
        "possible_keys": [
          "usergroup",
          "product_id",
          "company_id",
          "lower_limit",
          "usergroup_id"
        ],
        "key": "company_id",
        "used_key_parts": [
          "company_id"
        ],
        "key_length": "4",
        "ref": [
          "const"
        ],
        "rows_examined_per_scan": 7,
        "rows_produced_per_join": 2,
        "filtered": "32.81",
        "index_condition": "(`ea201_francemaqu`.`cscart_ult_product_prices`.`company_id` <=> 1)",
        "cost_info": {
          "read_cost": "2.00",
          "eval_cost": "0.46",
          "prefix_cost": "3.40",
          "data_read_per_join": "73"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "company_id",
          "usergroup_id"
        ],
        "attached_condition": "((`ea201_francemaqu`.`cscart_ult_product_prices`.`lower_limit` = 1) and (`ea201_francemaqu`.`cscart_ult_product_prices`.`product_id` in (11315,11308,10945,10936,10935,10934,10933,10900,10899,10568,10572,10570,10567,10574,10511,9952,9878,9422,9242,9240,9252,9253,9254,9255,9256,8666,9453,8580,8568,8579)) and (`ea201_francemaqu`.`cscart_ult_product_prices`.`usergroup_id` in (0,0,1)))"
      }
    }
  }
}