We have already discussed the regular Sunan in detail, and we mentioned that there are no regular Sunan to be performed before ‘Asr prayer.
Shaykh Ul-Islam Ibn Taymiyyah, may Allāh have mercy on him, said, “None of the scholars said that the Prophet (PBUH) used to perform any regular Sunnah before ‘Asr prayer. What was reported in this regard is either weak or even incorrect.” (Al-Fatāwā, 23/125)
Thus, the correct opinion, and Allāh knows best, is that no certain Sunnah is specified before ‘Asr prayer, but it is rather left unrestricted. Hence, if someone wants to pray two Rak‘ahs or more before ‘Asr as a general Nāfilah that is not specifically intended to be a regular Sunnah before ‘Asr prayer, he can do so as he would do at any other time that is not a time of prohibition. In conclusion, it is not allowed to offer a Sunnah prayer before ‘Asr prayer with the intention that it is specific to being before ‘Asr.