The Internet of Things (IoT) is a network concept that is critical to the development of smart environments. Wireless Sensor Networks (WSNs) are poised to revolutionise the Internet of Things (IoT). IoT-WSN data transmission schedules and channel access remain a major issue for effective system performance in IoT networks, though. The physical and medium access control (MAC) layer functions of an IoT device are the ones that consume the most energy. MAC protocols' energy efficiency has been extensively studied in the literature because of their fundamental importance. In this paper, Energy Efficient MAC protocol with Traffic-aware Wakeup Scheduling (TWS-EEMAC) is proposed for IoT-WSN. In this protocol, the lengths of duty-cycle of the IoT sensor nodes are determined based on traffic aware duty-cycle adjustment technique. In this technique, the awake period of the nodes are adjusted based on the number of contenders and the traffic load at the node. In order to determine the optimal number of contenders, Q-learning algorithm is applied. The proposed TWS-EEMAC protocol is implemented in NS2 and it shows superior performance in terms of end-to-end delay, packet delivery ratio, throughput and energy consumption.