Can a billion elliptic curve keys be generated on a laptop in less than an hour?
The very fastest elliptic curve algorithms can generate a key-pair in about 40k cycles on a modern CPU. A high end laptop has four cores running at about 3 GHz, so it can generate about 300k key-pairs per second, or a billion per hour. (The cost of SHA-256 is negligible in comparison.)

However, secp256k1 is nowhere near the fastest curve. It takes 10 times as long to generate a key-pair with many algorithms, according to the above link, so it would likely take tens of hours at least to iterate the search space. A more mainstream laptop and you may be looking at several days.

So if you just brute force generate key-pairs looking for a matching one, you can't get it done in an hour even with a much better implementation (unless you get lucky).