SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e549cca0dfa85a6281260d815b7db2d4b3bb457d2df1cb671b1d7f24cb557378' 
  AND token = 'uBOWwDAW/qezaoKd1fhoRvppYjzej8833amgruI7hlc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables