I noticed that too, I think he may be referring to the fact that generating super large actual prime numbers is hard, so people use probabilistic algorithms to generate probably almost primes
I haven't benchmarked it, but I think that should easily run in under a second on any phone sold in the last 10 years. If you do it a bit smarter and skip even divisors, I think it could run in under a second on 30 year old hardware (25k iterations, 200-ish cycles per loop (division was very expensive, back then) takes a 5MHz CPU)
At a generous one minute to prove primality of numbers in that range using trial division, and assuming you forget to bail out early when you find the first divisor, you still very likely will find a prime within an hour.
Even in the 70s, when computer time cost real money, that shouldn’t deter you.
(I just tried this on a Mac Mini, in Swift; finding 1000 primes took about a third of a second; 3 seconds if I forget to bail out early)
Edit: as further evidence that this isn't that large a prime: we knew 2^31-1 to be prime by trial division in 1772 (Euler somehow found time to do that)