A board like that likely uses jumper pins for clearing/resetting cmos not a button(usually only high end boards use a button). What does the motherboards manual show?
I have the Asus H110M-E and i have looked all over it to find the CMOS reboot button but i just cant find it
at bottom of board above usb3-12 header you will see a 3 pin header with a 2 pin jumper, it will say CLRTC next to it which means clear real time clock- your cmos.