https://www.law.cornell.edu/wex/statute_of_limitations
Also there are subtle questions around what discovery means here. Usually it is some sort of "could be discovered with reasonable effort". If I had proof of your wrongdoing in a letter sent to me, I am unlikely to get away with saying, "Oh, I didn't read the letter when I got it." If that proof was buried in a computer file with a million pages, I probably can reasonably say, "That was a needle in a haystack, and I didn't even know what to look for." For situations between those extremes, there will be case law that likely varies by state.
This is where a lawyer gets to earn their pay.
1030 actually has a specific discovery/statute of limitations in the text of the statute, and so may not be affected by state discovery rule law.
For example, say the statute of limitations for 18 USC 1030 is two years. If a person hypothetically stole a scooter by hacking, two years later, they would be in the clear, right?
No. The discovery rule says that if a damaged party, for good reason, does not immediately discover their loss, the statutes of limitations is paused until they do.
Accordingly, if the scooter company read a post today about a hack that happened “a long time ago” and therein discovered their loss, the statute of limitations would begin to tick today and the hacker could be in legal jeopardy for two more years.