SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7c1a276686120c04ddf832668f5ce97e8e1803b40665a94db6feeba50f9b21c' 
  AND token = 'Vg1HWTpwFcOxrQYm4bhlDX9yrld+UmlHM/H4q+o2JUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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