SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f98d0cec93ca09654f63ffd3a9a7813de9901340a2e1e91fb37a1247e723bea' 
  AND token = '2n9SS8kRydWLLCheKgtMGzBBkkzp+i6lRVC2DZ/h+zw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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