Through the ages there is much secret prayer, there is no announcement, it did not make the books of Church history, very few know what was prayed. God hears every prayer, He notices. Every prayer, short prayers, long prayers will be heard by God.
Another great quote from Hidden Life of Prayer by David MacIntyre
… the inner sanctuary. A solitary worshipper has entered within the veil, and hushed and lowly in the presence of God, bends before the glancing Shekinah. This represents the hidden life of prayer of which the Master spoke in the familiar words, “But thou, when thou prayest, enter into thine inner chamber, and having shut thy door, pray to thy Father which is in secret, and thy Father which seeth in secret shall recompense thee” (Matt. 6:6).