The obvious problem is that you don't have a repository with PHP
installed. It's odd that base doesn't have one but you can fix this by
installing the remi repository, which has PHP 5.4 through 5.6 (just
enable the version you want)
I would highly suggest installing
php-mysqlnd instead of
php-mysql, as that is the native driver and does not require
mysqlclientXX libraries, which are a mess to maintain.