Sunan an-Nasa'i — The Book of Purification — Hadith No: 19
Translation
It was narrated that Anas bin Malik said:"The Messenger of Allah (ﷺ) entered Al-Khala' (the toilet) and said: 'Allahumma inni a'uthu bika min al-khubuthi wal-khaba'ith (O Allah, I seek refuge with You from male and female devils)."[1] [1] See Ma'alam As-Sunan by Al-Khattabi. And Al-Khala' is the area one relieves oneself in. It refers to outside or other than that, it should not be understood to mean toilet only