SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = '52caac2254c15a3b78d55ad52099fb4d9df9de6d2ada29579d7784871be3f7a0' 
  AND token = 'tQZNN0GA4GZX6IjUeiMtAx7NmnKAJcQZpRiGnKxedio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00844

JSON explain

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