SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '488215f9a8fda2afb78be5632a76cabdb98afe4d91a0d03eafdae86346856f21' 
  AND token = '6BQcoXpt2mQ0vJEYoyUUglJ+7/9o7Dy6vVfUwwbbrdk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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