Electromagnetic switch
This link from Mouser discusses why there is a difference in the AC and DC rating.  It says:


  When an AC circuit is slowly broken, the arc or spark is extinguished
  quickly — a desirable condition (AC naturally has "current zeros"
  twice a cycle.) Conversely, when a DC circuit is slowly broken, the
  arc can be drawn much longer before it is extinguished. This is an
  undesirable condition which leads to pitting of switch contacts, which
  leads to overheating and premature failure of the switch, which can
  also lead to fire!


This link from a switch manufacturer has a rule of thumb for DC ratings.


  For those switches that list an AC voltage rating only, the "DC Rule
  of Thumb" can be applied for determining the switch's maximum DC
  current rating. This "rule" states the highest amperage on the switch
  should perform satisfactorily up to 30 volts DC. For example, a switch
  which is rated at 10A 250VAC; 15A 125VAC; 3/4HP 125-250VAC, will be
  likely to perform satisfactorily at 15 amps up to 30 volts DC (VDC).


From the rule of thumb, you should be able to use your switch for 24V DC at 1A.