SELECT 
  product_id 
FROM 
  cscart_product_popularity 
WHERE 
  product_id IN (
    10944, 10945, 10946, 10947, 10948, 10949, 
    10950, 10951, 10952, 10953, 10954, 
    10955, 10956, 10957, 10958, 10959, 
    10960, 10961, 10962, 10963, 10964
  )

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "4.56"
    },
    "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": 21,
      "rows_produced_per_join": 21,
      "filtered": "100.00",
      "using_index": true,
      "cost_info": {
        "read_cost": "2.46",
        "eval_cost": "2.10",
        "prefix_cost": "4.56",
        "data_read_per_join": "672"
      },
      "used_columns": [
        "product_id"
      ],
      "attached_condition": "(`gaseus`.`cscart_product_popularity`.`product_id` in (10944,10945,10946,10947,10948,10949,10950,10951,10952,10953,10954,10955,10956,10957,10958,10959,10960,10961,10962,10963,10964))"
    }
  }
}