How long is the timeout after which it is killed? What is the status of systemd-random-seed.service in that case? I don't see why it should take so long for the random number generator to initialize. But maybe apache2 needs to add a dependency.
Please provide the output of journalctl -b UNIT=apache2.service + UNIT=systemd-random-seed.service + _TRANSPORT=kernel|grep -i -e apache -e random when apache2 has failed to start.
