صَلَاةُ السَّعَادَة
Ṣalāt as-Saʿādah — Salawat as-Saʿadah
اَللَّهُمَّ صَلِّ وَسَلِّمْ عَلَى سَيِّدِنَا وَمَوْلَانَا مُحَمَّدٍ عَدَدَ مَا فِي عِلْمِ اللهِ صَلَاةً دَائِمَةً بِدَوَامِ مُلْكِ اللهِ.
Allahumma salli wa sallim `alaa Sayyidina wa Mawlana Muhammadin `adada maa fee `ilmillahi salaatan daa'imatan bi-dawaami mulkillah.
O Allah! Exalt and send peace on our Leader and Master Muhammad on the number of what exists in Allah's Knowledge, with ongoing prayers as long as Allah's Kingdom exists.
From the book Afdal as-Salawaat by Shaykh Ahmad as-Saawee, it is said that if you read this salawat once it is rewarded as if you said salawaat 600,000 times, and if you recite it seventy times a day you will be released from Hellfire.
Source: Mawlānā Shaykh Nāzim al-Ḥaqqānī ق & Mawlānā Shaykh Hishām Kabbānī ق, Ṭarīqat al-Naqshbandiyya al-ʿAliyya (sufilive.com)