Grading: Its chain is "sahih".

Reference / Source: Imam al-Bayhaqi recorded it in (3/208) from Abu Abd Allah al-Hakim with this same chain.

Reference / Source: Ibn Abi Shaybah (2/114) recorded it from Waki', from Isma'il bin Abi Khalid, with this same chain.

Reference / Source: Al-Tabarani (9493, 9494) and al-Bayhaqi in "al-Sunan" (3/208) and "Shu'ab al-Iman" (4634) recorded it via Abu Wa'il, from Amr bin Shurahbil, from Abd Allah bin Mas'ud (may Allah be pleased with him): "The length of the prayer and the shortness of the sermon are a sign of a man's understanding (fiqh)".
Technical note / Defect ('illah): Qays bin al-Rabi' combined this wording and the wording found with the author (al-Hakim) into a single hadith, and narrated it from al-A'mash, from Umarah bin Umayr and Malik bin al-Harith, from Abd al-Rahman bin Yazid al-Nakha'i, from Abd Allah bin Mas'ud, as marfu' to the Prophet (peace and blessings be upon him). Al-Bazzar recorded it in his Musnad (1908, 1909), while there is "weakness" in Qays bin al-Rabi'.

Important point: Both wordings together are authentically (sahih) established as marfu' through the hadith of Abu Wa'il, from Ammar bin Yasir, from the Prophet (peace and blessings be upon him).
Reference / Source: Imam Muslim recorded it in his Sahih (869), and it will come with the author at number (5788).