Keegan-Michael Key -- Good Genes or Good Docs?

Keegan-Michael Key's good looks are truly no joke!

Here is a 34-year-old version of the "Key & Peele" star at a Hollywood party back in 2005 (left) and 13 years later ... the comedian -- who celebrated his 47th birthday this past week -- at a party in Beverly Hills earlier this month (right).

"Why Him?"

The question is ...