SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36e524dde31c0c129cce91817d701bfc5f9ca51fa0be47a43a9e7b1c4414b0e4' 
  AND token = '3bo/YC/NYE9Da0eO/kkYDbuhB/EFdd3oEjwq1h+NWEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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