Lyon - 71 Tests, 280 wickets, 30 years old
Warne - 145 Tests, 708 wickets, ended his career at 38
Lyon could very well play another 74 Tests in the next 8 years, but he'd need to take 428 wickets in those. That's at twice the rate that he has taken his wickets so far. At his current rate, he'll need to play a total of 180 Tests before he could cross 708 wickets. That's another 109 Tests. He's going to have to be a regular in the Australia side for close to a decade, if not more, and yet maintain his current level of performances.
Seems quite unlikely tbh. However, for comparison, after 71 Tests Warne had 317 wickets. He was also 30 years of age. He would go on to take another 391 tickets in the back half of his career. So Lyon isn't that far off
Having said that, Lyon would have to bowl better than Warne did in his after-30 years, and most likely have to play on till longer than Warne did as well, in order to over take him.