SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0704e59ea3f860dd6529b6fcbb87f1fca73c2f964120d37888a9d3d3ca8139e0' 
  AND token = '0LXSHVIylvf6mXnPurYBxhfw5vjrLXeEWk4K9u4CqDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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