SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = '2486211b93150ec81ceab2fce5672aa96876f54c189be54a0e4b397d6bfc72c5' 
  AND token = 'nwrFpaw4QVZNuoI4h4ilYnyPmYg7KcGZ/2cUtiJhG1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00756

JSON explain

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