SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67d3d51684a9722ba8649ec6ec68af58b43b4195e5c8a8e3a07dfd3a208009de' 
  AND token = 'UhCSpxOhNPaXVQROk4KX1DHOsEShuT+DEUM8P2rhwGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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