SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ab0a69a3ac07af6445ea39a5cfc29d59b01102e734110281eee3b785298a0a5' 
  AND token = 'zmozSwNAkFe/sXH72zaRACSyZEQegbLGpgAqMwl3C+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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