يَا حَيُّ يَا قَيُّومُ بِرَحْمَتِكَ أَسْتَغِيثُ
Yā Ḥayyu yā Qayyūm, bi-raḥmatika astaghīth
O Ever-Living, O Sustainer of all, by Your mercy I seek help.
Jami at-Tirmidhi 3524, from Anas, graded hasan by al-Albani. The Prophet ﷺ said it when something distressed him; the hadith does not tie it to Ramadan