SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7cbc4d113fe16646a287650ea8392080dbe220e775796483c530f8e5d6c21d7' 
  AND token = 'YOXvtPhQXtwWG8Dlm0vGkle541NQwWygUFgPBaucHQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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