SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c493b9b0346d157d40c05e46bc4e50f23cff66d7d3c677c7b26c22b5153d68f' 
  AND token = 'UUQu32eznmnHf+0TMDT6PpTmbMYi7hEGWgMBgC444GY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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