SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '100f6edc7dbd97c749452fc0c63347398661b45105b5763550dddac8f19cdf69' 
  AND token = 'DGdB7VBTjzGvWOlpgFZkB/BhGgS5mw1x8SdPojASWy0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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