Yes it is possible, you can restore an API key from the API keys section of your dashboard: https://www.algolia.com/api-keys/restricted
Then you can paste in the key you need to restore and press restore:
There is more detail on this here: https://www.algolia.com/doc/guides/security/api-keys/how-to/how-to-restore-an-api-key/#using-the-dashboard
Deleted API Keys after team member removal
When removing a user/team member from one of your applications, you just need to double check that the API keys that are being used in your search implementation or the extension configuration settings are not the ones that belong to that user. This is because all API keys associated with that user will be deleted when the user is removed, and if the application is depending on their keys, it will break.
Please note that if there were some team members leaving your organisation and there were API Keys attached to some of those users, restoring this API Key is only recommended as a temporary fix. On these cases we recommended to create new API Keys and set those on your code. You can find more information about our security best practices on this documentation: https://www.algolia.com/doc/guides/security/security-best-practices/#securing-your-api-keys
Finally, as a safeguard against this problem we recommend only using the API keys of the user that is the owner of the Application in your production App. This is because the owner's API keys are never deleted (unless you manually delete them yourself).