In this scene, Lucifer Morningstar processes the universe's 20,000,000,000 Year history in the blink of an eye. Now, I know Lucifer is 1-A and thus Irrelevant in speed, but this is being done for the fun of it.
I'll assume Lucifer's blinking lasted 100 miliseconds, or 0.1 seconds.
20,000,000,000 billion years is 6.31138519e17 seconds.
Now, how to do this?
The Human Brain is capable of processing around 60 bits of information per second:
https://www.technologyreview.com/s/415041/new-measure-of-human-brain-processing-speed/
Now Lucifer processed everything that ever happened in the universe over a period of 20,000,000,000 years. So, how many bits does the universe has? Well, people are huge nerds, and someone on MIT has actually calculated this (Go figure):
https://arxiv.org/pdf/quant-ph/0110141v1.pdf
This is a really long paper full of weird calculation, but it reaches the calculation that over 10 billion years, the universe must have performed 10^120 operations on 10^90 bits. So for a 20 Billion year old universe, it'd be 20^120 operations. Multiply both and you'd get a total number of 2.0e210 bits.
Lucifer processed this in 0.1 seconds.
2.0e210 / 0.1 seconds = 2.0e211 bits per second. Diving that by the human processing speed...
2.0e211 bits per second / 60 bits per second = 3.33333333e209.
This means that Lucifer can process information at speeds 3.33333333e209 times faster than ordinary humans.
This number should logically scale to Lucifer's reactions. Now we know that average humans can react in 0.3 seconds. And MFTL+ Reaction Speeds (x1000 speed of light) start at 0.000000000003336 seconds or 3.33600e-12 seconds. So let's have some fun.
0.3 / 3.33333333e209 = 9.00000001e-211 seconds.
Lucifer can react in 9.00000001e-211
3.33600e-12 / 9.00000001e-211 = 3.70666666e198
Lucifer's reaction speed is 3.70666666e198 times faster than baseline MFTL+
So 3.70666666e198 x 1000 = Fucking 3.70666666e201c, or 3.70666666 Sexsexagintillion times Faster than Light.