Memento mori is a caution against excessive pride. We are all equal in the grave and we are all going to die. Memento mori tokens or reminders were carried by powerful people to remind them to temper their decisions and maintain humility. Definitely not the "fuck it" attitude of YOLO.
Memento mori = Remember that you are going to die
Carpe diem = Enjoy the day
YOLO = enjoy your life, because you only have one and you are going to die
It does if you remove it from its context where they used it more like "you should be humble, you'll die like everyone else", carpe diem was used more similarly to yolo
YOLO is a little more... eh.. pro-active? Knowing that you are going to die is not quite the same as saying fuck-all and leaping to a possible death. However, there are multiple contexts for YOLO, so there is that.
I think the similarity comes from the literal meaning of the two but doesn't extend beyond that. "Memento Mori" carries a distinctly humble meaning related to the concept of "vanitas", the idea that death is inevitable, even for the rich and powerful, and that earthly pleasures are vain and meaningless. That's really in the opposite direction of YOLO.
I think memento mori means more like "remember that someday you will die like everyone else" - so pretty much "be humble". The ancient Romans used to say that to generals when they returned from a successful campaign as to remind them that they are not almighty.
I would definitely argue that it is at least technically correct.
Your example points to a vague resemblance in how it sounds spoken, which has barely nothing to do with the meaning. This much ought to be obvious.
My thought points to an unlikely lesson found in both phrases. That is, both remind to make the most out of life, because inevitable death. As others have pointed out, the connotations just have been formed such that YOLO ends up generally achieving that with recklessness and "Memento Mori" generally with caution and healthy respect for mortality.
However, that does mean that the same lesson is still found in them, which indeed makes them mean pretty much the same thing. Note that I don't claim them to be synonymous, like a certain comment claims, or interchangeable, which they aren't.
TL;DR: Your example relies on how it sounds and it is indeed superficial. In my thought the similarity indeed exist in the language and is technically correct.