اَللّٰهُمَّ خِرْ لِيْ وَاخْتِر لِيْ ـ
Allaahumma khir lii wakh-tar lii. [Abu Bakr. Sunan at-Tirmidhi #3438]
O Allah, choose and select for me.
When a person is faced with a decision and there is no time for Istikhaarah salaat, this du’aa can be said repeatedly instead.
(Source: Khalid Baig’s transliteration, translation and commentary of du’aa #132 from the Accepted Whispers: Munajat-e-Maqbul)