SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdb2ad0d727d78ccd4f34187d8f3609094f60b39254712bb713b65302228c49e' 
  AND token = 'VBxidXv9/yIhcv2UMYlRo7AI2oWT9UaqXXKEYZx9L4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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