Using late 2009 21.5” iMac as screen for Toshiba windows 10 laptop

I’ve been deep in forums to find an answer for this, but keep getting different information:

Can I connect my Toshiba laptop to my late 2009 21.5” imac using a HDMI to mini display port cable so that I can use the iMac as a screen for my laptop? I don’t want it be be a second screen, just a mirror display of what is on the laptop, so I can keep the laptop closed. I don’t need it to work the other way so it would just be HDMI to mini display, not the other way around. Target display mode isn’t available for the iMac I have. Is this possible using just a cable?

I know this isn’t what they’re designed for, but I’m hoping I can give the iMac a bit longer life using it as a screen, and saving my eyesight from looking at the laptop :)

I appreciate any help!