EUREKA — A 23-year-old signed away the next 45 years of his life by pleading guilty Friday to first-degree murder in Woodford County Court.“Yes, sir,” “No, sir,” and “Guilty” were the only words spoken by Rayshawn Lamar Johnson during his court appearance before Circuit Judge John Huschen. Johnson confessed to police as recently as two weeks ago that he shot and killed 74-year-old Oakley Mitchell at his rural Secor home in early August.