SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '273f651712c9e881f83e55c082582003df787f5f7c0fb38276f9ea05def4325b' 
  AND token = '8xksh+5jIysLOAOi0Jq88wKqs7fZK+gpoX6Y45lA1b4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

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