SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c6815b23cf424b78179808e059c34b8f1941078a2ad8a31a084a35ac1ddadf3' 
  AND token = 'V9e2aNVi4CvNvXylONmHHdm0zWq2dbfqXlpXz6wUDSw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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