Checkbox change logic

Hello, I want to create a checkbox using the MDTF plugin which will display only the current posts but there is a problem because Checkbox returns 0 – false and 1 – true. To create a checkbox, I used the meta key but metakey returns 0 or nothing – when the post is current, and the value 1 – when the post is expired and now the checkbox when it is selected shows only the posts that are expired. How can I change the operation logic so that the selected checkbox returns all values except – 1 (true)?