SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c869b3bfc44e925b6aa02f23430dc1cd6628d41c6402653bab784347d2468ef' 
  AND token = 'duMzTxIqVIs8yx4j5vO6h0RORDzSsU7rTw7K0SmMBTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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