SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15217b7c51db3e7ed9412c61b3cc24a8f95c7934ccf80fe5646dc25f0319fed5' 
  AND token = 'KruxTDVaTXbNgHpzxfyEeVpO9g6FkA0VFkUJTKmSkJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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