SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7f3856f644d4cd573a267c75ad478b417eade5eda1ad4019673799f7bbfedfa' 
  AND token = 'T1/eV1BXcw/F3juZM0fjt3ZBNQV+4VKpJk3SArmCPnk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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