Modern versions of SQLyog (v12+) use online validation. Even if you find a key, the software will phone home, detect the fraud, and either deactivate itself or lock you out after 30 days.
SQLyog offers different types of licenses to cater to various user needs: sqlyog license key
SQLyog offers different types of licenses to cater to various needs and budgets. The main types of licenses are: Modern versions of SQLyog (v12+) use online validation