Look for a boot with 400/600 or maybe even 800 grams depending on how cold your feet get.
I wear these (I have wide feet and they make an excellent boot if you want a wide toe box)
Meindl built the perfect insulated waterproof hunting boot to get you from opening day to that last winter blizzard. 9" all leather uppers with Meindl's exclusive Comfort Fit last and cork footbeds, these boots provide extra room in the toe box and mold to your feet for a custom feel. Made in...
meindlusa.com
I just got back from the Allegheny in PA for bow hunting and was in 32 degree or less weather for several days straight. Snow, sleet and rain with high winds daily. I had zero issues with my feet getting cold. I then went to the NY side for opening day of deer season for rifle and it snowed and sleeted there as well. In both locations I was averaging seven hours a day in a saddle and in a tree. I had no issues with my feet getting cold.
Your sock is also a huge part of the equation also. I wore these daily and love them. They also have a life time warranty.
This is our burliest hunting sock. When it's crazy cold, but you're still going out, this is your sock for hunter boots. Available charcoal gray and forest green.
darntough.com
There are several boot companies out there making varying levels of insulated hunting boots. I was just using mine as an example. Same with the socks.
Hopefully this helps a little.