SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54b635eef1e7a488f08da98f26fb743b9244a2ca5af1628576b35dd2dd1fee0a' 
  AND token = 'asvAjjDAY4AW+oENFylglTKPp8rIhKca6J0fZHgG3gY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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