SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d00406ce025429430312110194215c5618c70389005cd990982064ddb0a66fc' 
  AND token = 'iUeRxp4lhq5Fx7kvGM3YIvRNRGqYvt/YNwrZ9EXhkNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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