By default, it starts like this:
> grep -e ^Exec= /etc/xdg/autostart/gnome-keyring-ssh.desktop
Exec=/usr/bin/gnome-keyring-daemon --start --components=ssh
Resulting in:
> echo ${SSH_AUTH_SOCK}
/run/user/1000/keyring/ssh
The keys from ${HOME}/.ssh
should be added automatically.