Secures a specific exchange rate for a limited duration to facilitate a buy or sell transaction.

Upon success, it returns an fxLockId and an expiration timestamp (fxLockExpiryAt). This ID can be provided during the execution phase to ensure the transaction uses the locked rate, protecting the user from rate fluctuations during the flow.

While rates are typically managed on a daily basis, locking ensures consistency for the duration of the user's specific transaction session.