SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9924ac3672f688c25a136458b1d451fa7ae358ad69eae8db0cd3a6230e8d140f' 
  AND token = 'hGzBibEB0HG6w0NTHPYqKt0jyTDh91mLhIJYPHVy6D8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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