SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3cccf06a8320dcb721d4f0183c98823e7bdc54ea3a95d2f4e83ba8fe347d7ee' 
  AND token = 'LNBXysmGNk8BIvZ6QjnFCn6EwzmggwIwWhUwjX+grg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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