I lost the last 5 minutes searching for the page where I could get my API key ;) -- Finally, i found it at the (very discrete) link into the "Logged as ..." at the page left top.

At the page top right, currently there is three options: "DNS Manager", "Change password" and "Logout"

I suggest to change this "Change password" option to a more abrangent "My Profile" or "Profile" option which would open the current "logged as ..." page. And then, inside this page, put the "Change password" option.