«أَوْ يُفْتَدَى عَيْشٌ مَضَى»
Or if a vanished life could be redeemed by ransom.
Yuftadā is passive, from the form associated with redemption or ransom. ʿAysh maḍā denotes a life that has passed away. The conceit is knowingly impossible: time cannot be purchased back.
The poet imagines giving an extraordinary ransom to recover his former years. As a figure of longing, the unreal condition makes the contrast between remembered happiness and present deprivation sharper.