SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5d7831518749083167c9af7b8ce7aaebdeb13072f93eed4a56f26df7a7695371' 
  AND token = 'XiXoSXMYbu2Zmi38OyKTIccWx9Vpidved7toUHsfQKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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