I need a solution

[wispy burrow]

You need something called atomic locks to ensure that a value can't be read while another process is modifying it. The query builder allows you to use shared/exclusive locks, and the Cache also has a lock feature that makes it easy to implement a mutex. Both are described in the docs.

I think in your case you could use the query builder's lockForUpdate() to ensure that multiple processes can't update the same row simultaneously.