SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b98fd602f171ee80b278009e2a5c78db85ff9bedae737f39f1bb5f37bd4de5f' 
  AND token = 'e8eadC0A8p9/Lt7msJXt82VOy/b778nDR/jkvN+5Ero=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

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