SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f4f0372355fc23663d986b7a4ef8d06843fae582fb87724b44e9177a615d919' 
  AND token = 'lF0I/0QTCbzPgo8Xwh3CleBLDyyHuQmNd+utrPKjJ4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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