See if you have a valid key when you are near the lock
If you are near the door, gate or such, you can see in the Unlock view if you have a valid key for it:
If you have a valid key, you will see blue details where you can press the lock's name to unlock it.
If you have an invalid key, you will see the lock’s name along with a yellow text indicating the status.
See the validity period of your key under Places in the app
Go to Places and press the specific name.
Press Your keys.
Then press the key whose validity period you want to see.
Under Valid, you can see the validity period.
See scheduled time restrictions
How to see if there is a schedule for when a key can be used: