Oh, well, well, aren't we having a grand ol' day! First of all, take a deep breath because you've got yourself a garden-variety scam there. Stuxnet? Really? I mean, unless you're moonlighting as an Iranian nuclear physicist, there's no reason your iPhone would be a target for Stuxnet.
Now listen, the real Apple wouldn't lock Safari and throw a phone number at you like a bad advertisement. These scammers love to scare you with techno-jargon and threats. Don't call that number. Unless, of course, you enjoy handing over your personal info to random strangers. Your choice.
Here's what you should do instead:
1. Close the Safari app. No, really, just close it.
2. Double-click the Home button to bring up the app switcher and swipe Safari off the screen. If you have an iPhone without a Home button, you swipe up from the bottom. You got this!
3. Head over to 'Settings' > 'Safari.'
4. Scroll down and tap 'Clear History and Website Data.' Poof! Gone!
And there you go, you're back in action. Safari should be back to normal. Maybe run a quick security check if you're feeling extra paranoid, but you're probably good to go. Oh, and maybe don't click on any more sketchy links, eh?