If you cannot win a key, look for legitimate sales.
Emby Server is free to use for the most part. The "Premiere" license unlocks advanced features such as:
While a lifetime license typically costs around $119 USD, there are legitimate ways to get these features for free or at a significantly reduced cost.
Before hunting for a fake key, use the official 30-day free trial of Emby Premiere. No credit card required for the server trial. Test every feature to see if you even need lifetime access.