SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4cbf1d433ac9a9be80ad55653bf707537f7a5740bfef1508bbe2bf0acf93d02e' 
  AND token = '4oRT3QtTz6fzb4ZkwhbGHi4ebZ0/MWtvxGcgrXs1gbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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