SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '268885be0ee08782426235969e1384628b539e5726414e2b203004a84dcb9767' 
  AND token = 'hbYuDRQQuLKKNYZ+aopnyQ1au1CDZwphi7VsAR0HgVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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