How can one obtain the reward for awaiting prayer and for Ribat between Asr and Maghrib, when mosques close immediately after Asr prayer and do not open until just before Maghrib?

The reward for awaiting the prayer after the prayer is not exclusive to the mosque; rather, it includes anyone whose heart is attached to the prayer and whose mind is occupied with it, whether they are in their home or at their work, provided that Allah knows the sincerity of their intention.