SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '720e70729c743a88ce31f566a0208c8d1c121ad8ae1c12c63c77840681d07aa2' 
  AND token = 'ttATYxZZVXHbOOO72a1Vnw2i+VSK1H9ZrJC/bCatqOU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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