SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83512305739427c32233a89b91eb008f4cc8a9438ff384dd3d21e33d09c3ac92' 
  AND token = 'rduM5dkYBKtF3OcaN4cOLerEt/xe5gb+3Jj5tWp7O+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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