How to check if specified id does not exist in two tables in MySQL?

I have two relational tables.

table 1 staffs_items

item_id   int(11)
staff_id  int(11)

table 2 entries_items

item_id   int(11)
entry_id  int(11)

I want to check if an item_id does not exist in both tables.

like this:

SELECT EXISTS ( SELECT * FROM staffs_items AS si WHERE si.item_id = 1 ) AS exist;

+-------+
| exist |
+-------+
|     1 |
+-------+

SELECT EXISTS ( SELECT * FROM entries_items AS ei WHERE ei.item_id = 1 ) AS exist;

+-------+
| exist |
+-------+
|     0 |
+-------+

I want to run those queries in a one liner.

If item_id does not exist in either table, I want to return 0 (false).

How can I do that?