On the host machine you can use the ssh-key and ip subcommands of the minikube command:
scp -i $(minikube ssh-key) <local-path> docker@$(minikube ip):<remote-path>
So the command from the question becomes:
scp -i $(minikube ssh-key) /media/myuser/sourceFolder docker@$(minikube ip):/home/docker/destiationFolder