The real-time database service selection depends typically to the system stability in order to handle the time-constrained transactions within their deadline. However, applying the real-time database system in the mobile ad hoc networks requires considering the mobile nodes limited capacities. In this paper, we propose cross-layer service selection which combines performance metrics measured in the real-time database system to those used by the routing protocol in order to make the best selection decision. It ensures both timeliness and energy efficiency by avoiding low-power and busy service provider node. A multicast packet is used in order to reduce the transmission cost and network load when sending the same packet to multiple service providers. In this paper, we evaluate the performance of our proposed protocol. Simulation results, using the Network Simulator NS2, improve that the protocol decreases the deadline miss ratio of packets, increases the service availability and reduces the service response time.