All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
The Hadeeth in question was reported by Ahmad, Abu Daawood and At-Tirmithi from Ibn ‘Umar that the Prophet, sallallaahu ‘alayhi wa sallam, said: "May Allaah have mercy upon the one who prays four Rak‘ahs before ‘Asr." Ash-Shawkaani said in Nayl Al-Awtaar after stating that Hadeeth: "At-Tirmithi deemed it Hasan (good) while Ibn Hibbaan and Ibn Khuzaymah deemed it Saheeh (sound)."
Also, Shaykh Al-Albaani deemed it Hasan and thus the level of this Hadeeth is at least Hasan.
For more benefit, kindly refer to Fataawa 84719, 83409 and 82005.
Allaah Knows best.