SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '0b7552e1e50af76e96728c260c531dc97b187e41a039e0ad9810f1812456efff' 
  AND token = '3zCX/cW2ImMwj283uYuCFNDqFTGN+ZTgVmrfhwoah2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}