Adding to what @truemate says:
1. That key is valid until January 31, 2021, so you can use CCleaner Professional until that date, after that reverted to Free version.
2. The following key can ONLY be used for CCleaner Pro version 5.63.7540, upgrading to a newer version automatically invalidates the license as it was stated “No Free Updates“.
@Alex42, you need to keep this mind.