To use a YubiKey with LastPass, you need to have a LastPass Premium, Families, Enterprise or Teams account.
Any YubiKey configured with a Yubico OTP works with LastPass (with the exception of the Security Key, which supports U2F only). The Yubico page on the LastPass site lists the benefits of using YubiKey to protect your LastPass account. For instructions on how to associate your YubiKey with your LastPass account, see YubiKey Multifactor Authentication in the LastPass user manual.
The LastPass Mobile Device Application supports YubiKey two-factor authentication using the YubiKey NEO on Android and iOS mobile devices. For more information, read Introducing YubiKey MFA on iOS for your LastPass Account.