SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a509d1f3b2aa7d0764a8ce7f34bd9edbbadf943fdddaf8a0cbd07db1a5585ae2' 
  AND token = 'Xj7TY7IUJTlfBHy2Y8ZuP91LXwaNb5I0ug1HPxDCV0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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