SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e85555f4101b45ddfbae51edc8230315862c39f3e0bb41d21535f3d67736ac37' 
  AND token = 'ApzWkUBsbDNZxlRzPYUyt6jLCBSDEm9EDZW+3oKdQRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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