SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cac47c476106ee421e2fab33ce207c6f97819f8d3cbb515edd4fa61d492bbf7' 
  AND token = 'Qqdtrx8BdxV3HsWRXc77MK0rD0960YyCYDP6Pzb3O44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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