Hey there, MaksoKv!
Good news -- While Riot does lock accounts found to be hacked, this is often just a suspension for the protection of the account owner, and can be reversed once you have proven you are the original account owner.
So don't worry! This is likely a preventative measure so no one can cause damage to your account. Just submit a ticket to Riot Support and await their response -- they'll help you figure out what the problem is and how to fix it, and you'll be back on the Rift before you know it! It can take them up to a day or two at times, so be patient: they have a lot of player tickets to answer. Don't panic and try to bump your ticket -- all that does is send it to the end of the queue again.
Worse case scenario is that your account has thrown up red flags for some other behavior, and in that case Riot Support can help you figure out what's wrong and what steps you can take to resolve the issue.
Make sure you consider changing your password to something more secure and being suspicious of any League-related links that aren't Riot official: there are a number of ways people may try to get into an account, but if you're cautious you can minimize the chances.
Best of luck!