SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '095b1c39f721deef8145ba6569407c3eb6bdcbee7436ed8863990a0ee2c25c68' 
  AND token = 'bPqnWksIVGGm27HJZn6rHS3AjrxGAwxjXeQtKge+pRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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