SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c16c6b9e4f893185edb310f715bcf40dbcbd97e11cf19a6fdc879d59a1b1662' 
  AND token = 'd5uf3qrN+dnulOou5MXRsThboD9tvEqQqoAnJLkO8rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}