In both of my responses I had already said to enable the interactive sensor as that will push the keyguard state faster in the apps current state.
Looking deeper in the android code there might be a broadcast intent for when the keyguard itself has been removed so we will need to do further testing on that.
To utilize this today before we get the app updated you will need to register for this intent using the Last Update sensor and adding the constant value from the link as an intent in the sensor settings
When you follow the steps to register for the intent this will basically force all sensors to update when your device emits that a user is present. From there you should see the sensor update immediately, then once we get the app updated you can safely remove the setting as the app will already have it registered for you. If you try this now and tell me that the intent works for your use case I can get a PR submitted.
Now this intent will only tell you when the keyguard has been removed, if you want to understand when the user is gone then you will need to use the interactive sensor for that because that sensors utilizes the screen off intent.
Not all sensors offer a way to update instantly which is why the app updates all of them anytime one sensor has an update. The more you enable the more updates you can expect to receive.