Grading: The hadith is sahih, but as the narration of "Abu Hazim from Sa'id al-Maqburi from Abu Hurayrah" (as mentioned earlier at 3639).
Technical note / Defect ('illah): As for this narration of Hammad bin Zayd, he made a "mistake" (wahm) in it, as al-Daraqutni pointed out (al-'Ilal 8/ 133). Abu Khaythamah Zuhayr bin Harb and Yahya bin Ma'in also mentioned Hammad's error in it (Mughaltay 4/ 141). This is supported by the fact that Khalaf bin Hisham (thiqah) narrated it from Hammad bin Zayd and said, with doubt: "from Sahl bin Sa'd or someone else" (al-Ruyani 1068, Abu Nu'aym 6/ 265). This shows that Hammad did not retain it accurately from Abu Hazim, and two thiqah narrators also contradicted him.

Reference / Source: As for the hadith of Sahl bin Sa'd, it was recorded by Ishaq bin Rahawayh (Musnad), al-Tabarani (al-Kabir 5933), Ibn Mandah (al-Tawhid 105) and Ibn Marduyah through several routes via Sulayman bin Harb, and in it they said "sixty years", not seventy.

Reference / Source: It was recorded by Ali bin Abd al-Aziz al-Baghawi in his "Musnad" (al-Matalib al-'Aliyah), and from him by al-Tabarani (5933), via Arim (Muhammad bin al-Fadl), from Hammad bin Zayd, and in it too he said "sixty years".