How do I find civil death registrations for Kerepes, Hungary for 1921?

Kerepes is in Pest county, which did not participate in the records-conservation contract with FamilySearch. Its civil registrations are only available at the county archive in Budapest (Vágóhíd utca 7).

(Note that the current Pest county is not the same thing as the old Pest-Pilis-Solt-Kiskun county. It's the current jurisdiction that counts for availability, but things are filed under the old jurisdiction on FamilySearch. This is a frequent source of confusion.)