SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91ac4037cace3f4f3cbf167dc1f731b609424fda7de4547185ae3f93f098f0f3' 
  AND token = 'SFZj7pBWuCVa/yQjGAj3sFZJw2UHen7pc9AKiEz4Urs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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