SELECT 
  product_prices.product_id, 
  MIN(
    IF(
      product_prices.percentage_discount = 0, 
      product_prices.price, 
      product_prices.price - (
        product_prices.price * product_prices.percentage_discount
      )/ 100
    )
  ) AS price 
FROM 
  product_prices 
WHERE 
  product_prices.product_id IN (
    138903, 171934, 139416, 139364, 139389, 
    139360, 138902, 139368, 173441, 139376, 
    139318, 139415, 139314, 139315, 139377, 
    149277, 139381, 139366, 139363, 139387, 
    139379, 139418, 139321, 139361, 139419, 
    173429, 149275, 139380, 139355, 139358, 
    139372, 139383, 139390, 138901, 173431, 
    173432, 149249, 173426, 138899, 173436, 
    149261, 149274, 139370, 173443, 139367, 
    173438, 139385, 149278
  ) 
  AND product_prices.lower_limit = 1 
  AND product_prices.usergroup_id IN (0, 1) 
GROUP BY 
  product_prices.product_id

Query time 0.00155

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "39.86"
    },
    "grouping_operation": {
      "using_filesort": false,
      "table": {
        "table_name": "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": 48,
        "rows_produced_per_join": 4,
        "filtered": "10.00",
        "index_condition": "(`goimagine`.`product_prices`.`product_id` in (138903,171934,139416,139364,139389,139360,138902,139368,173441,139376,139318,139415,139314,139315,139377,149277,139381,139366,139363,139387,139379,139418,139321,139361,139419,173429,149275,139380,139355,139358,139372,139383,139390,138901,173431,173432,149249,173426,138899,173436,149261,149274,139370,173443,139367,173438,139385,149278))",
        "cost_info": {
          "read_cost": "39.39",
          "eval_cost": "0.48",
          "prefix_cost": "39.87",
          "data_read_per_join": "115"
        },
        "used_columns": [
          "id",
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`goimagine`.`product_prices`.`lower_limit` = 1) and (`goimagine`.`product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}