Malaysian Airlines have, over the past 18 months been replacing their old 737-400 / 500 series planes with the latest 737-800 version. The withdrawn planes have in the main been sold to other airlines (although a few have been scrapped for spares)
Looking at the banner draped over the fuselage looks like this one has been brought by private charter company
AF Jets. They specialize in executive charter and specialist freight haulage, and as the 737-400/500 planes are popular with companies who do this kind of service, I suspect this one is being trucked by road pending conversion to a freighter.