SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f69c3e3ab8de16c70a38922a295cda07dce2e0dc550938684123def680a85316' 
  AND token = '0ILYAzuaTwC3Pgg3vL1QjRidGJbbtqdRVHfOixJBZTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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