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 (
    190720, 190686, 190711, 190675, 190708, 
    190716, 190712, 190700, 190710, 190709, 
    190721, 190722, 190680, 190701, 190717, 
    190714, 190679, 190715, 190681, 190694, 
    190685, 190677, 190688, 190687, 190678, 
    190682, 190684, 190702, 190704, 190703, 
    190706, 190707
  ) 
  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 0.00146

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "89.71"
    },
    "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": 64,
        "rows_produced_per_join": 64,
        "filtered": "100.00",
        "cost_info": {
          "read_cost": "76.91",
          "eval_cost": "12.80",
          "prefix_cost": "89.71",
          "data_read_per_join": "4K"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`webmarco`.`cscart_product_prices`.`lower_limit` = 1) and (`webmarco`.`cscart_product_prices`.`product_id` in (190720,190686,190711,190675,190708,190716,190712,190700,190710,190709,190721,190722,190680,190701,190717,190714,190679,190715,190681,190694,190685,190677,190688,190687,190678,190682,190684,190702,190704,190703,190706,190707)) and (`webmarco`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}