The lexar will probably be "fast enough". I would get the less expensive memory card first, see how much you use it. See how quickly your buffer fills up writing to the card, and then maybe considering getting a faster card later one.
If you need to upgrade later on, at least you will also have a second memory card as backup with the lexar.
Technically the camera supports uhs-1. I am not sure when you would want to use all 12fps in the camera though. (Of course I've been doing a lot slower photography lately.)
Canon 5DIII, Rebel XTi/400D
Canon EF 16-35mm f/2.8L II, 24-105mm f/4L, 50mm f/1.4, 70-300mm f/4-5.6 DO, 85mm f/1.8
Sigma 150mm F2.8 EX Macro
Sigma 10-20mm f/4-5.6 EX, Canon EF-S 18-55mm f/3.5-5.6 II
Canon 430EX II
Opteka 13mm, 21mm, and 31mm extension tubes
Vivitar 50mm f/1.8 for OM System