SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6664bda47627aa15ae36249a81ab08f49167a61a59de2bc7d07395f53a2c00b9' 
  AND token = 'FfbTKgZeNi7UYYRT9YvE4gU3npppqy3yPS34+h57n90=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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