SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '108f1a071e56c9ab1dbc003701eb5e33d9ebb8c0617b2ab0048cdffa16969cc0' 
  AND token = '6UroVAL7qBcAvo8ZbdZNzhIUFd88T52urUa2bLNHICc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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