Channel Ops have always been able to "lock" their channel by setting modes +mints. Now in newer versions of Unreal we can be a bit more specific. ie modes +RM etc.
Additionally, mode +k isn't just an unreal thing. it's rfc1459 required so all ircds should support it. Anope definately supports it, you just can't mlock modes with additional parameters like k,l or ircd specific modes like unreal's f or j.
With that said, I think a bit more information about what exactly you mean/want would be beneficial. Please be specific as to what you are wanting and expecting.