If you store keys in a database that is separate from the columns encrypted by those keys, you must load both databases from dumps that were made simultaneously, avoiding a problem where the encrypted column’s key is missing after the load.
After loading the databases for keys and data, bring both databases on line simultaneously.
Before dumping the database containing the encrypted columns, use alter table to decrypt the data.
Dump the databases containing keys and encrypted columns.
After loading the databases, use alter table to re-encrypt the data with the keys in the newly named database.