SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41081b5fd316aa8382e2b2a615c995ca5a0df1e464bd706146a134f9186d8f6d' 
  AND token = 'YcObo5UJRxBvyxrxp4/15m9qGzDwJqBXmV5XMRYzgAc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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