SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '87f7c253363fb6520c7d5f48482697c18a2d02b5fd7ab8c5c4aef3aeaf962426' 
  AND token = 'Vl9Ox0LOi7YkwH6x4h1DTrJ8Fo+t/UWMnG+U1mFAO/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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