SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcb81eaca53db4da2d987524b46dc501212311e94ab5cb28e7072f9aca195151' 
  AND token = 'iFwwvXkwm2mRHsARrmCLaWynXnsaeh4P9jdzy2bpJG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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