SELECT 
  product_id 
FROM 
  cscart_product_popularity 
WHERE 
  product_id IN (
    12506, 12505, 12514, 12513, 12512, 12511, 
    12510, 12509, 12508, 12507, 12516, 
    12515, 12517, 12518, 12519, 12520, 
    12522, 12521, 12523
  )

Query time 0.00066

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "4.15"
    },
    "table": {
      "table_name": "cscart_product_popularity",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "total"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 19,
      "rows_produced_per_join": 19,
      "filtered": "100.00",
      "using_index": true,
      "cost_info": {
        "read_cost": "2.25",
        "eval_cost": "1.90",
        "prefix_cost": "4.15",
        "data_read_per_join": "608"
      },
      "used_columns": [
        "product_id"
      ],
      "attached_condition": "(`test2_gaseus`.`cscart_product_popularity`.`product_id` in (12506,12505,12514,12513,12512,12511,12510,12509,12508,12507,12516,12515,12517,12518,12519,12520,12522,12521,12523))"
    }
  }
}