SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57efae655b0bbbe633040180cec4caa2d471b22a6da1e1f8d789f5ed5935b3fe' 
  AND token = 'BIDuLk8DuaohkgsSFYxRyR1+lO+nKzWqfnlWxEaZGKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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