SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ad0cb1bf18789d22b172c97f030e8d8970ef4fd4f9dcc632b165d3a4711576e' 
  AND token = 'bycHcQ4TqOkTijQemSNcLFmB/1ce4pcskxbiptbSu+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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