SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd175516f3149c76189c95db9d815ce8678cfe56ff85752194191defb91bf185f' 
  AND token = 'd9KIbsNgc79CmzaTySuzbzJaHa8qiSSLIFj+mpHGIk0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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