download mysqlclient fra https://www.lfd.uci.edu/ ~gohlke/pythonlibs/#mysql-python
vælg den version, der matcher din python-version, eksempel mysqlclient-1.4.2-cp37-cp37m-win_amd64.whl, og derefter:
pip install wheel
pip install mysqlclient‑1.4.2‑cp37‑cp37m‑win_amd64.whl