Can she look around whilst praying to check on her children?

Praise be to Allah.

Firstly: 

You should not pay any attention to the whispers of the Shaytaan with which he tries to distract people from their prayers and from focusing properly in the prayer (khushoo‘). 

Secondly: 

Before starting to pray, the Muslim should deal with anything that may distract him from his prayer. If you can pray at a time when the children are sleeping, that is better, and you should hasten to pray before they wake up. 

If it is possible for you to leave your daughters with someone who will watch them so that you can focus on your prayer and not be distracted by anything else, then do so. 

If you can distract the children with some toys or cartoons, then do that. If it is not possible for you to do that, then keep them with you in the room and close the door. By doing that, there will be no need to worry about them, and you will be able to deal with a lot of this waswaas yourself. 

Thirdly: 

There is nothing wrong with you looking around whilst praying in order to check on them if need be, if there is something that really necessitates looking around. There are some hadeeths which indicate that there is nothing wrong with looking around whilst praying if there is a need to do so, as has been discussed previously in the answer to question no. 160647. 

Please see also the answer to question no. 5485 

And Allah knows best.