SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '43088ed29de973a44305dde973727870734148e202706dd5fda6385c3edf037f' 
  AND token = 'e8MHQ+7TmKDYjuF0L4k9GJkO9XVnbvKHU9e2y8TqHMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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