SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0146b3976446a1ec9b6757fea291c9da79239b4d9df241a1d7e17e15e0097953' 
  AND token = 'SDXfgMjgui/9ZxXeMfDK6SIvMe77Y0SZrJo2k0rVt4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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