SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aec8fc2f5b9aad449ff8deaefcbe49c6eb56620e1355a7efd9815489a3c5a318' 
  AND token = 'K3KLAqP31gceJxPAXNA3T5ZwOmr97sjGGVRYzlA+WpU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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