After a ssh-keyscan I opened my generated known_hosts file, and found that there are 3 instead of 1 key for my EC2 instance.
**.**.**.** ssh-rsa ******
**.**.**.** ecdsa-sha2-nistp256 ***
**.**.**.** ssh-ed25519 ***
Are they all being used when logging in? Can I safely delete from them if some are not used at all?