SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52973819888789c261d051fdaf7843ba0efe778c831d142abe0db6bc3faee566' 
  AND token = '/SmNSIlDqVGSeXcck60YRzZwSWNpKJIA0Nm1hxn1WMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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