SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29376e2af450841703446be079ebff23aa9b9e28406a6458ca105b1a5693bf37' 
  AND token = 'LLJugwh3LnX+OzT0zmRz5+ElhD3EbQlIY0rFDZE73RE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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