Currently:
The problem is that MySQLdb or Oursql is required and I didn't managed to get any of them working.
Found this but didn't manage to get it working neither.
Edit: If you are aware of an other orm that works with Python3, I'm interested.
I was successful in getting Oracle's MySQL connector for python working with SQLAlchemy on Python 3.3. Your connection string needs to start with "mysql+mysqlconnector://...". After I changed my connection string everything (well, simple things) started working.
The MySQL connector docs can be found here: https://dev.mysql.com/doc/connector-python/en/
The package is up on PyPi: https://pypi.org/project/mysql-connector-python/
Here are the SQLAlchemy docs about using the Python connector: http://docs.sqlalchemy.org/en/latest/dialects/mysql.html#module-sqlalchemy.dialects.mysql.mysqlconnector