What is the actual ratings of this limit switch?
The markings/ratings you look at and work with depend on which approval/testing/listing agency you're most concerned with.
The 5A/125VAC, 3A/250VAC ratings have been tested/approved/listed by UL and/or CSA.
The 5A/250V~ rating has been tested/approved/listed by some other agency who's mark I am not immediately familiar with.  

Since in your application you're only planning to work with 2A/24V, and you're presumably not planning to sell your device (at least not into any market where approval from one of these agencies is required), you should be well within the limits of all of these ratings and you shouldn't see any problems using this switch (but do take care to protect it from back-EMF spikes if you're switching an inductive load).