Aerospike is like a massive hash table, and does not work like a SQL database. A Key is a hash of what you pass to the NewKey function, and has nothing to do with any bins in the record.
Either use the (normalized) email as the key instead of ID (recommended), or first find the record via a query, extract its key, and then use it to change other bins in the same record. (not recommended, since it does not scale well)
Normalization in this scope means that you should convert the email to lower case, remove the white space around it, etc. to make sure you always end up with the same key.