I don’t actually think it’s that bad. Needs some color correction maybe before you bring it in to AE. Looks like it’s not white balanced right, but it keyed pretty easily over here.

That’s what I did. You can tweak. Came out a little yellowy, but I usually key with Keylight and Color Key. I drop both on to the layer and then select the main background color with Keylight. Then I turn keylight off.
I then select a color with Color Key and remove it with a slight feather. Then I duplicate that and select another remaining shade of green and remove that. And so on and so on. Once everything is removed I turn on Keylight and adjust (as shown) to smooth the key out.
Then, in this case I color corrected horribly. But you get the idea.