SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'faaa992666101948a37fc4d018a1128e99e43012e42cab20713217465160d200' 
  AND token = 'uj6vey+E1Ms8zVoLge2G7Io0hLReRkoYQ/oGUnXhIww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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