SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa9ec54d94665113bc8df20a9b85cf909b633c54027f59bf6aa70fa7b858c36d' 
  AND token = '2ZVx+xMhomXwJxzH3v9iw9OzyZ0hEVMczNbQz/zV0Fw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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