SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5df260e012a1cf71959825ef09dce2b320b7874ce86602adf99d1157f4b43e35' 
  AND token = 'XFBizpv6ZTGxDkGq3lqStYnlhIL6H+1xd9iS6SJhxks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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