I think the italicized tubes is what you meant to ask, so I'll answer accordingly.

Tires are labeled by the manufacturer with a specific size. In your case 700x45. Tubes are very elastic, and as such can fit a pretty wide range of tire sizes. Think of it in terms of T-shirt sizing. A tube marked 700x35/45 will reliably fit in a range of tire sizes from... 700c x 35 up to 700c x 45. You could probably even get it to work in larger tires. Smaller tires and large tubes get a bit tougher, because it's hard to stuff that much rubber inside the tire and get the beads on the rim without pinching it. In T-shirt terms again, you can fit a skinny guy in a XXL t-shirt and he'll still have a shirt on, but try to squeeze a fat guy in an XS and it gets tricky.

Tubes labeled for smaller tires, when stuck inside bigger tires do stretch thinner though, and at extremes can leave you prone to more flats.

I run 26 x 1.75/2.0 tubes in my 650b x 2.3 (roughly 27.5 x2.3) tires without any issues other than having to stretch them some. I know guys who run 26" tubes in their 29" tires.

So with far fewer words, yes, you want to use the 700 x35/45 tubes, but look for some with a Schrader valve.