SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec99a7aba22130041852aa5ebea019dbe104c3351042771fe83a717f0fcfb273' 
  AND token = 'CgtB2W9FCGjzFJ5iSJCGkTAb8D8Pu8kcrC5dkeVmltI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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