This package is depending on dev-python/mysql-python which is broken and abandoned by upstream. You should attempt to switch to dev-python/mysqlclient which is a continued fork of mysql-python. Please test that it works like it's supposed to, so broken mysql-python can be last-rited and removed from the tree.
the ebuild is currently wrong because it misses something like: REQUIRED_USE=mysql? ( || ( $(python_gen_useflags python2*) ) )" which won't be needed when switching to dev-python/mysqlclient
Seems like this is "fixed" via https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=14c7369dbffeebf01c9005bb4a2f9f89f50f5e88