SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e37a018300060400097432f975388142fd88e37a8e2d2222cb9aeccc516868a8' 
  AND token = '/Z1L9v5VbGa8hkPuM0Kg9YxOaNJDkzSlfDhwleUkssI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}