Do unselected checkboxes need to be >4.5 contrast ratio to be WCAG AA compliant?

I'm trying to understand the details of WCAG AA compliance. Would the unselected checkboxes in this image be considered too low-contrast to be compliant? Is there anything we can do (other than change the color) to make it more compliant? If tab-focus makes the contrast go up, is that enough? Or do we really just need to boost the contrast?