The word(s) "locks" appears 7 time(s) in 5 verse(s) in Quran in Saheeh International translation.

(1) And when he came to the well of Madyan, he found there a crowd of people watering [their flocks], and he found aside from them two women driving back [their flocks]. He said, "What is your circumstance?" They said, "We do not water until the shepherds dispatch [their flocks]; and our father is an old man."

(2) So he watered [their flocks] for them; then he went back to the shade and said, "My Lord, indeed I am, for whatever good You would send down to me, in need."

(3) Then do they not reflect upon the Qur'an, or are there locks upon [their] hearts?

(4) The criminals will be known by their marks, and they will be seized by the forelocks and the feet.

(5) And He sent against them birds in flocks,