It doesn’t expire though. It renews itself if one of the following happens. According to https://firebase.google.com/docs/cloud-messaging/android/client: -The app deletes Instance ID.
Read moreCan I send a push notification to Android?
Navigate to Settings > Mobile Apps. Click the mobile app for which you’d like to send a push notification . For Device Token, enter the token you located above. For Message, enter a message to display in the push notification.
Read moreHow do you handle Firebase push notifications?
For sending FCM notification payload you can use Firebase Cloud Messaging Tool in firebase console . And click on Send your first message. Then enter the Title and body field. If you wish to send it to a particular device then click on Send test message and enter the FCM registration token.
Read moreHow do I get push notifications on Android?
Turn on notifications for Android devices
Read moreHow do I get push notifications on iOS?
Instructions
Read moreHow do you send actionable notifications to iOS with Firebase?
Send messages to multiple devices on Apple platforms
Read more