Thank you mdooley for your comment.
Your input, made me to think more deeply about this issue.
I thought that this problem is probably related more to Lightdm then to power options that is driven by systemd.
So i have found that inside: /etc/lightdm/lightdm-gtk-greeter.conf.d
There was a config file: 99_ubuntu-mate.conf
And inside of it i saw line: active-monitor=0
I have replaced “0” with “1” and that solved my issue.
I have learned more today!
Thanks again.