SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = '8ed72dab405264989bbd50646527d0f462d4dcdce57c952024350d01aeef97a2' 
  AND token = '9iEqYG2W1QJABmIvuguxLL71+sqsUX6zZFF02vahPsI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00892

JSON explain

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