SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52fd6585a2207e889a3d528c8293ebf9387ae06306ebff7aa40fe3b8f5607293' 
  AND token = 'JJmXZPJEDtfhnZ9zvi6ncBtJx40KIrjQ/wmnMCao6Gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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