SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = 'd8b0d288609a136d6f33743ecdf62e45d952f0d95036f86379aabc0c2499f338' 
  AND token = 'BHAyEHp2H+UdSvpZDQMhLDitVpEKv8pl6jYT3WGQnWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00817

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}