You need to block wind, have toe wiggle room and keep feet dry.
My solution was SPD keen bike sandals (can loosen considerably) with the rubber toe bumper (blocks wind), thick wicking wool socks ("Blazer" bought at Performance), insulated Pearl Izumi toe covers between socks and shoes (additional wind blocking).
The back of the sandals allowed moisture to be lost but since those areas of the foot have thicker skin and don't face into the wind, they don't get cold.
The thick socks made the toe cover bottom cutouts more comfortable .
The rubber shoe insole protects against the cleat coldness.
My part of the country 40F is considered cold, it doesn't go below 32F without iced-over roads here. Typically my hands get cold before my feet do. 75 minutes is doable with this setup.
I have closed mountain bike shoes that I am wearing in the fall but I'll go back to the sandals for winter. The shoes just won't loosen up enough for the thick socks.
I also have medium-weight wool socks but they don't seem any warmer than my tightly-knit summer synthetic socks.
I got some motorcycle boot liners but I think the lack of wicking will make my feet too damp.
I tried neoprene socks but they were too tight, the seam was uncomfortable, and my feet stayed wet.
Instead of plastic bags, you can use Glad Press-n-seal wrap to just cover the forefoot over your socks. You can re-use them a few times. They help block wind.
An analogy from when I went skiing - I had better luck with thin socks than thick. I needed toe wiggle room more than I needed heavy socks.