SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a159ecdbedcecf5caed0a83f6ebc7e56bc471606f8c36d5dd08bea12b4dc2b79' 
  AND token = 'fnXlW5FbrzIw6xSgfLerXpXWAEAq0Lreb0d6DLEfGnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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