SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f3241cb3f3bc9dbb3669ee627c7bedc4ccca370225be9358095fa9b6cb5904d' 
  AND token = '4ZhGiEYelmQDqr0LHMKS8yvmId31C8noKJIsoQkBP0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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