SELECT 
  COUNT(*) 
FROM 
  cscart_wishlist_items 
WHERE 
  product_id IN (
    65239, 65240, 65241, 65242, 65243, 65244, 
    65245, 65246
  )

Query time 0.00484

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "487.13"
    },
    "table": {
      "table_name": "cscart_wishlist_items",
      "access_type": "ALL",
      "rows_examined_per_scan": 4828,
      "rows_produced_per_join": 2414,
      "filtered": "50.00",
      "cost_info": {
        "read_cost": "245.73",
        "eval_cost": "241.40",
        "prefix_cost": "487.13",
        "data_read_per_join": "37K"
      },
      "used_columns": [
        "product_id"
      ],
      "attached_condition": "(`chocoramo`.`cscart_wishlist_items`.`product_id` in (65239,65240,65241,65242,65243,65244,65245,65246))"
    }
  }
}